There are many situations in which pedestrians may be carrying materials which are prohibited from transport into or out of a designated area. Some examples are airports, sporting arenas and high security facilities. The prohibited materials may include, for example, explosives, drugs or even a product being stolen.
One method for screening for various materials is to individually search each pedestrian for the prohibited material. Unfortunately, individual searching is extremely time-consuming and requires an inordinate number of searchers and an inordinate period of time.
It is known that many prohibited materials such as explosives and drugs emit odors which are distinctive and can be detected in very small quantities by dogs or other animals which have been trained to identify such target odors. However, bringing certain animals into direct contact with a large number of pedestrians presents difficulties. Some people are fearful of certain animals and a person being screened may cause harm to a highly trained dog or its handler.
What is needed, therefore, is a reliable, consistent, and rapid system to screen persons or conveyances and obtain consistent positive identifications of prohibited material while minimizing false-positive identifications of prohibitive material.